SLIPPERY SOILS - SLope instability In Polar PERmafrost - dYnamics of frozen debriS lObes In the ALaskan BrookS Range
Université de Genève
Université de Genève
Lay summary
SLIPPERY SOILS aims to improve our understanding of frozen debris lobes (FDL) dynamics in the Brooks Range, Alaska. Across the Arctic, rates of mass movements are expected to accelerate in response to warming-driven permafrost thaw, and the proposed research will provide a key long-term perspective to better understand how sensitive FDL are to climate warming. Because they are forested, our long-term reconstruction of FDL dynamics will come from dendrogeomorphology, the use of tree rings to precisely date and quantify the activity of past geomorphic processes.
The project will test three hypotheses: (i) leaning and subsequent reaction wood in trees record past near-surface flow in FDL; (ii) the location and orientation of split trees and exposed roots, which correspond to stresses within the near-surface soil of the lobe, can be used to accurately date the onset and rates of spreading episodes or zones of differential movement within the lobes; (iii) given their sensitivity to recent air temperature variability and change, reconstructed FDL dynamics are supposed to also respond to past warming and cooling for which data is hitherto missing.
There has been relatively limited application of tree-ring analyses in permafrost terrain. This work will also be the first to couple photogrammetric and tree-ring analyses to determine 3D surface changes and related tree behaviour on landslides in permafrost environments over time. Lessons learned from this research can be applied elsewhere where permafrost-stabilised slopes are prevalent. This includes other forested landslides that threaten infrastructure and management goals in the Gates of the Arctic, Denali and Wrangell-St. Elias National Park, as well as elsewhere in Alaska. This also includes alpine permafrost as FDL are an integrative part of the continuum of slope movement processes in permafrost. While these research results will increase understanding of FDL dynamics, the approaches developed here can therefore be used to determine long-term movement rates and surface dynamics for other FDL-like features within the Arctic, and in more temperate mountainous regions.
Details
| Regional focus | Arctic |
| Location | Brooks Range, Alaska |
| Funded amount | 50,000 CHF |
| Project dates | 1st May 2023 – 31st January 2025 |
| Category | SPI Exploratory Grants |